For at least the last 50,000 years, and probably much longer, people have practiced religion. Yet little attention has been given, either by believers or atheists, to the question of whether this universal human behavior might have an evolutionary basis. Did religion evolve, in other words, because it helped people in early societies survive? In this original and controversial book Nicholas Wade, longtime reporter for the New York Times Science section, gathers new evidence showing why religion became so essential in the course of human evolution, and how an instinct for faith has been hard-wired into human nature.